Securing devices, such as cables or wires, are often used in orthopedic surgery for securing bones in place and for fastening implants, such as plates, to the bones. In one type of procedure, a cable having a pair of opposite ends is positioned around one or more bones. The cable has a connector at one end, and the other end is inserted into the connector to form a loop of the cable around the bone or bones. As used herein, the term bone may refer to a bone, a bone fragment, or a portion of a bone. The term cable may refer to metal and non-metal cables, wires, or other elongate securing devices that are configured to be tensioned by a tensioning instrument.
A tensioning instrument may be used to apply tension to the cable and constrict the loop of cable about the bone or bones and an implant, such as a bone plate. Tensioning instruments may be very complex and include, for example, a cable locking mechanism, a cable tensioning mechanism, a detachable re-tension mechanism, and a tension scale. Some prior tensioning instruments use different mechanisms to provide each of these features, which increases the cost and size of the tensioning instrument.
Some surgeries require multiple cables to be implanted that each require tensioning. One prior tensioning instrument that may be used in such a surgery is a pistol-type tensioner having a detachable tip for holding tension in each surgical cable. During surgery, the tensioning instrument is used to apply a desired amount of tension to a first cable, the tip is engaged to the cable to hold tension in the cable construct, the tip is detached, a new tip is connected to the tensioning instrument, and the tensioning instrument is moved to the next cable. This procedure is repeated until all of the cables have been tensioned. Connectors on the cables are then crimped to secure the cables on the bones. One problem with this approach is that once a cable has been tensioned and the tensioning instrument detached from the tip, the tension in the cable may change, for example, due to tensioning of another cable around nearby bones. In that case, re-tensioning of the cable would be necessary. However, the operator would not be aware of the change in tension unless the tensioning instrument is re-connected to the first tip and used to gauge the tension in the first surgical cable.
Some known tensioning instruments have numerous components, are relatively large, and are quite complex. These instruments are designed to be reused, due to their relatively high cost and complexity. However, complex instruments are often difficult to clean properly after use, often requiring a skilled technician to disassemble the instrument and clean individual parts before reassembling. Accordingly, complex tensioning instruments are relatively expensive and are associated with ongoing cleaning expenses with each use.